1. Technical Field
The present invention relates to a chip manufacturing method of separating a first substrate and a second substrate bonded to each other into chips, a liquid ejecting head manufacturing method, and a liquid ejecting apparatus manufacturing method.
2. Related Art
As a liquid ejecting head used in an ink jet printer and the like, for example, an ink jet recording head that is obtaining by laminating a nozzle plate having an nozzle opening, a flow path forming substrate provided with a vibrating plate or a piezoelectric element and a reservoir forming substrate has been known. JP-A-2008-119905 discloses a manufacturing method of dividing the flow path forming substrate and the reservoir forming substrate bonded to each other into a plurality of silicon devices with a laser beam. The manufacturing method discloses forming an elastic film made of silicon dioxide on a silicon substrate, forming an insulator film made of zirconium oxide on the elastic film, bonding the reservoir forming substrate on the insulator film in a section to be cut using an adhesive, forming a concave portion on the flow path forming substrate of the section to be cut by leaving the elastic film and the insulator film thereon, and then irradiating the reservoir forming substrate with the laser beam. In this case, a condensing point of the laser beam is focused within the reservoir forming substrate to leave a connection section on a surface layer, and therefore a fragile section having a predetermined width is formed within the reservoir forming substrate. Then, an external force is applied to the flow path forming substrate and the reservoir forming substrate, and therefore the flow path forming substrate and the reservoir forming substrate are divided into a plurality of the liquid ejecting heads along the fragile section.
The above-described flow path forming substrate is provided with a communication section configuring a portion of the reservoir. Therefore, the liquid ejecting head becomes long in the longitudinal direction of a pressure generation chamber. Therefore, it is disclosed that the size of the liquid ejecting head in the longitudinal direction of the pressure generation chamber is reduced in a way that the reservoir is formed out of the flow path forming substrate and a portion of a wall surface configuring the reservoir is configured by a side wall of the flow path forming substrate and a protection substrate (see JP-A-2011-62830).
The technique disclosed in JP-A-2008-119905 is that the elastic film made of the silicon dioxide and the insulator film made of the zirconium oxide are left in the section to be cut of the flow path forming substrate without a metallic film. The elastic film and the insulator film transmit the laser beam whose condensing point is focused on the reservoir forming substrate and thus do not become the fragile section. Therefore, when the external force is applied to the flow path forming substrate and the reservoir forming substrate, these substrates are not divided along the fragile section of the reservoir forming substrate. On the other hand, in order to remove the elastic film and the insulator film of the section to be cut, another step is required.
Even when the reservoir is formed out of the flow path forming substrate in order to reduce a size of the liquid ejecting head in the longitudinal direction of the pressure generation chamber, at least the elastic film made of the silicon dioxide is left in the section to be cut of the flow path forming substrate, which becomes an edge of the reservoir, without the metallic film. Similarly, since the elastic film through which the laser beam whose condensing point is focused on the reservoir forming substrate is transmitted does not become the fragile section, when the external force is applied to the flow path forming substrate and the protection substrate, these substrates are not divided along the fragile section of the reservoir forming substrate. In addition, the edge of the reservoir side cannot provide a lead electrode for connecting the reservoir to a drive circuit of a piezoelectric element.
The above-described problems are similarly present in various methods of separating a first substrate and a second substrate bonded to each other into chips.